In 1978 the country was rocked by Law and Order, a TV show depicting bent coppers, corrupt solicitors and a legal system run to suit itself.

It caused an outcry, but once the dust settled, work started on the Police and Criminal Evidence Act of 1984, which regulated police powers.

Now, 40 years later, BBC4 is showing all four parts. Leading the first episode is Derek Martin as DI Fred Pyall, who viewers will recognise as EastEnders’ Charlie Slater.